Msn家族激酶在血小板活化和血栓中的功能机制研究和血小板致密颗粒分泌调控网络构建

A common end event of nearly all vascualr diseases is the formation of platelet thrombus, which is directly responsible for mortality and morbidity associated with major cardio-cerebrovascular diseases such as myocardial infarction and cerebral infarction. Secretion of platelet granules constitutes a vital step in regulating thrombus and vascular homeostasis. We have previously identified an important regulator of platelet dense granule secretion, namely MINK1, a member of Msn kinase family. Based on this finding and further experiments, we hypothesize that Msn kinase family may constitutes the central core of platelet dense granule secretion network. Activities of Msn kinases are regulated by phosphatase PP2A, which is co-localized with Msn kinases in STRIPAK kinase-phosphatase complex, and further targeting to SNARE protein family-mediated dense granule secretion through MAPK and PI3K-Akt pathways. This hypothesis will be tested both in vitro and in vivo, using multiple newly constructed knock-out mice models. This study will delineate the signal network regulating platelet dense granule secretion, and provide novel molecular markers and intervention targets for cardio-cerebrovascular diseases.

血小板活化导致的血栓是各类血管性疾病的共性终末事件，是心肌梗塞、脑梗塞等致死致残性重大疾病的直接原因。血小板颗粒分泌是调控血栓的关键细胞事件。综合Msn激酶家族成员MINK1是血小板致密颗粒分泌的关键调控分子的发现与进一步的预实验基础上，本项目提出假设，Msn家族激酶受到STRIPAK复合物中的磷酸酶PP2A调控，继而通过MAPK和PI3K-Akt通路联系SNARE家族靶向致密颗粒分泌，调控血栓。我们拟通过已经构建完成的多个基因敲除小鼠和分子生物学研究手段，明晰血小板致密颗粒分泌的信号网络，为心脑血管性疾病的发生发展提供新的分子标志及干预靶点。

血小板激活为止血功能所必需，同时也是引起致命的血栓性疾病的原因。但区分止血和血栓的血小板调控机制不明。Traf2-和nck相互作用激酶(TNIK)是一种丝氨酸-苏氨酸激酶，作用于丝裂原活化蛋白激酶(MAPKs)的上游。MAPKs是维持血小板止血功能的重要信号，也是oxldl诱导血小板活化的重要途径。通过构建巨核细胞/血小板特异性TNIK缺陷小鼠，我们发现TNIK是血小板激活和止血性血栓形成所必需的，其作用主要为调控血小板致密颗粒的分泌，机制上由MLK3/MKK4/JNK通路介导，我们同时还发现，TNIK抑制氧化低密度脂蛋白(oxLDL)引起的血小板活性，从而抑制高脂肪饮食(HFD)诱导的促血栓状态。这些数据说明了血小板TNIK在止血刺激和高脂血症刺激下的双重作用，表明TNIK可能是维持血小板活性稳态的重要调节因子。本研究首次发现了血小板中的功能稳态维持蛋白，并对其机制进行了完整阐述，研究为血小板生物学了提供重要的新的机制发现入口，对脂代谢异常引起的血栓疾病防治提供新的靶点。